一台虚拟机做中继，令一台虚拟机同步时间
1.先安装ntf
[root@mysqlb ~]# yum install chrony
[root@mysqlb ~]# systemctl start chronyd
[root@mysqlb ~]# systemctl enable chronyd (开机自启)
[root@mysqlb ~]# vim /etc/chrony.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 0.centos.pool.ntp.org iburst
server 1.centos.pool.ntp.org iburst
server 2.centos.pool.ntp.org iburst
server 3.centos.pool.ntp.org iburst
# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift
# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3
# Enable kernel synchronization of the real-time clock (RTC).
rtcsync
# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *
# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2
# Allow NTP client access from local network.
#allow 192.168.0.0/16
allow 192.168.88.0/24 在88网段
# Serve time even if not synchronized to a time source.
#local stratum 10
用 chronyc sources查看
[root@mysqlb ~]# chronyc sources 210 Number of sources = 4 MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^+ h199-182-204-197.ip4.unm> 2 10 377 765 +9769us[ +10ms] +/- 108ms ^* b9d1-55de.led01.ru.misak> 2 10 377 304 +6515us[+7153us] +/- 72ms ^- 195.148.70.254 2 10 375 35m +6299us[ +11ms] +/- 212ms ^+ electrode.felixc.at 3 10 153 316 -1574us[ -937us] +/- 163ms
切换另一个虚拟机
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.centos.pool.ntp.org iburst
#server 1.centos.pool.ntp.org iburst
#server 2.centos.pool.ntp.org iburst
#server 3.centos.pool.ntp.org iburst
server 192.168.88.101 iburst
# Record the rate at which the system clock gains/losses time.
driftfile /var/lib/chrony/drift
# Allow the system clock to be stepped in the first three updates
# if its offset is larger than 1 second.
makestep 1.0 3
# Enable kernel synchronization of the real-time clock (RTC).
rtcsync
# Enable hardware timestamping on all interfaces that support it.
#hwtimestamp *
# Increase the minimum number of selectable sources required to adjust
# the system clock.
#minsources 2
# Allow NTP client access from local network.
#allow 192.168.0.0/16
[root@slave1 ~]# chronyc sources 210 Number of sources = 1 MS Name/IP address Stratum Poll Reach LastRx Last sample =============================================================================== ^* localhost 3 6 377 56 -211us[ -21us] +/- 73ms